Device for joining by calendering at least one sheet of glass and at least one film of plastic material

ABSTRACT

A calendering device has a plurality of pressure rollers and an opposing plurality of counterpressure rollers, each rotatably mounted on a piston rod movable in a direction for permitting the pressure rollers and counterpressure rollers to approach one another to calender a product. The pistons of the piston rods are mounted within pneumatic casings and are moved by a diaphragm within the pneumatic casings. There is no contact between the pistons and the walls of the pneumatic casings, thereby reducing the frictional resistance to the movement of the rollers. Means are provided for equalizing the pressure applied to a roller and its corresponding counter roller. Separate pneumatic casings and diaphragms may be provided for each piston rod, or several of the pressure rollers or counterpressure rollers may be moved by a single diaphragm, which can be in the form of an elongated hose. In the case of the provision of individual pneumatic casings for each roller, pressure regulating means can be provided for each pair of a pressure roller and its corresponding counterpressure roller.

.Iadd.This application is a continuation of application Ser. No.07/794,661, filed on Nov. 18, 1991, now abandoned., which is acontinuation of application Ser. No. 07/425,310 filed on Oct. 20, 1989,now abandoned. .Iaddend.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is concerned with a device for joining by calendering atleast one sheet of glass and at least one film of plastic material. Thedevice is composed of a series of pressure rollers mounted side-by-sidein a flexible manner and cooperating with the pressure rollers, it beingunderstood that the pressure rollers and the counterpressure rollers areeach mounted at the extremity of a piston rod, the other extremity ofwhich bears a pressure piston actuated by pneumatic pressure and movingin a pneumatic casing.

2. Discussion of the Related Art

Calendering devices of this type are used particularly in themanufacture of automobile windows of laminated glass which arecylindrically or spherically curved, and serving to calender thicknessesof glass and plastic material to be joined or laminated in such a mannerthat the air occluded between these layers is expelled as far aspossible and that a temporary reciprocal joining of the various layersis obtained. Thanks to their flexible mounting, the position of theindividual pressure rollers adapts itself to the particular shape of thelaminated window. The final joining together of these layers iseffected, after a preliminary pressing operation, in the course of anautoclave process involving high temperature and high pressure.

In the case of a known calendering device of the aforementioned type(U.S. Pat. No. 2,983,635), the pressure required is produced bypneumatic jacks in which the pressure piston is in direct contact withthe inside wall of the cylinder of the jack, and in this manner providestightness for the cylinder chamber into which the pressure isintroduced. In the case of this known arrangement, the mobility of thepressure rollers leaves much to be desired, due to the inevitablyproduced friction, and consequently the risk of breaking is increasedduring the calendering of the laminated window. Because of the frictionof the pressure roller in the cylinder of the jack, it becomesnecessary, during a change of the shape of the glass sheet, to first usea relatively great force, to wit, the so-called "tearing" force(difference of the frictional force between the static friction and thesliding friction), in such a manner that the piston overcomes the staticfriction at the level of the cylinder wall. The tearing force requiredfor the individual pressure rollers may, in this case, assume valuesexceeding the bending stress permissible for a glass sheet, so that itresults in breaking of the glass sheet.

SUMMARY OF THE INVENTION

The invention has as its object to improve a calendering device of thetype specified in such a manner that the frictional forces acting in theguiding and securing system of the individual pressure rollers arereduced and the positioning forces thus necessary to change the positionof the individual pressure rollers are markedly reduced.

This object is realized according to the invention by providing betweeneach pressure roller and the inside wall of the pneumatic casingsurrounding it, a spacing for preventing any direct contact between thepiston and the inside wall of the pneumatic casing. Inside the pneumaticcasing the space where the chamber may be subjected to pressure isisolated from the pressure piston by a very elastic diaphragm of rubberymaterial, which, under pressure, fits against the surface of thepressure piston's extremity and, by tightly closing the space betweenthe piston and the inside wall of the pneumatic casing, transmits thepneumatic pressure to the piston.

The individual pressure pistons have no sealing function to perform withregard to the walls surrounding them. As a result, there is no frictionloss between the surfaces of the piston and a wall of the cylindertightly surrounding it. To the contrary, the walls of the piston do notcontact the lateral sealing surfaces, but move freely in the pneumaticcasing without lateral contact with other surfaces.

The pressure pistons do not necessarily have the shape of pistons in thestrictest sense. It suffices if, for example, they have the shape ofsimple pressure plates which transmit the pressure applied by thediaphragm on the guide rods carrying the pressure rollers.

According to an embodiment of the invention, each individual pressurepiston is arranged in its own pneumatic casing which is provided with ahighly elastic diaphragm that acts only upon this pressure pistonarranged in the pneumatic casing. An advantage of such an arrangementlies in the fact that the pressure applied by each piston rod can beregulated independent of the pressure applied by the neighboring pistonrods. In this manner, it is possible, for example, to set a pressurecurve by which the pairs of pressure rollers situated in the center ofthe system exert a stronger pressure than the pairs of lateral pressurerollers, which, if necessary, permits squeezing out the air occludedbetween the layers.

According to another embodiment of the invention the pressure pistons ofseveral pressure rollers and counterpressure rollers arrangedside-by-side can be mounted without mutual contact in a common pneumaticcasing, the very elastic diaphragm of which, which closes the pressurefed chamber, acts simultaneously on all the pressure pistons arranged inthe common pneumatic casing. In the light of this, the pressure pistonsof all the pressure rollers arranged side-by-side, on the one hand, andthe pressure pistons of all the counterpressure rollers arrangedside-by-side, on the other hand, can be mounted in a common pneumaticcasing, and a very elastic diaphragm can be provided inside thepneumatic casing acting simultaneously and jointly on all the pressurepistons of the respective pressure rollers or counterpressure rollers.Such an arrangement presents a simplified structure, on the one hand,while on the other hand it assures in a particularly simple manner thatthe same pressure will act upon all the pressure and counterpressurerollers. Moreover, this arrangement has the advantage that by virtue ofthe elimination of the individual pneumatic casings, the pressurepistons can be arranged at the shortest distance from one another insuch a way that the pressure rollers can be of a narrower type, whichmeans that for the same width of the calendering device, a larger numberof pressure rollers can be provided.

The pressure rollers can be arranged indiscriminately in any spatialarrangement. If the pressure rollers, on the one hand, and thecounterpressure rollers, on the other hand, are mounted relative to eachother in such a manner that the piston rods carrying the pressurerollers are guided horizontally, a calendering system is obtained inwhich the laminated window to be joined by calendering traverses thesystem in a vertical position. Such a system is advantageous, forexample, for calendering large and heavy sheets of glass for which, inthe case of a horizontal calendering operation, difficulties can arisedue to the heavy weight of the glass sheets themselves.

Smaller sheets of glass, for example, of the size of windshields ofautomotive vehicles, are advantageously calendered in a horizontalposition in such a manner that the pressure rollers, on the one hand,and the counterpressure rollers, on the other hand, are mountedside-by-side, and that the piston rods run in an essentially verticaldirection. In the case of such an arrangement of the pressure rollers,where the piston rods move in the vertical direction or in anessentially vertical direction, it is advantageously possible tocompensate for the vertical force components produced by the weight ofthe guiding equipment of the pressure rollers and/or of thecounterpressure rollers. In the case of an exact weight compensation, itis possible that the pressure rollers remain in the height position theyrespectively occupy, which markedly facilitates the operation ofinserting a curved or bent sheet of glass between the pressure rollers,for example. Pneumatic springs with an essentially linear working curveare particularly suitable for the proper weight compensation of thepressure rollers and/or the counterpressure rollers.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and attendant advantages of the presentinvention will be more fully appreciated as the same becomes betterunderstood from the following detailed description when considered inconnection with the accompanying drawings in which like referencecharacters designate like or corresponding parts throughout the severalviews and wherein:

FIG. 1 is a front elevation view of a calendering device of theinvention having a common pneumatic casing for all the pressure rollersand another common pneumatic casing for all the counterpressure rollers;

FIG. 2 is a side elevation view in partial section of the calenderingdevice illustrated in FIG. 1;

FIG. 2A is a detail of FIG. 2;

FIG. 3 is a front vertical section of the calendering device of theinvention, in which each piston rod carrying a pressure roller at oneextremity is individually fitted in a separate, adjustable pneumaticcasing;

FIG. 3a is a view, on a larger scale, of a detail of FIG. 3;

FIG. 4 is a side elevation, in partial section, of the calenderingdevice shown in FIG. 3;

FIG. 4A is a detail of FIG. 4;

FIG. 5 is a front vertical section of another calendering device showingthe same basic structure, but using an elastically deformable continuouscylindrical body arranged under the pressure rollers to uniformlydistribute the pressure;

FIG. 6 is a side elevation in partial section of the calendering deviceshown in FIG. 5; and

FIG. 6A is a detail of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the calendering devices shown in the drawings, the axes of rotationof the rollers 1, 2 are in substances directed horizontally, and thepressure rollers 1 as well as the counterpressure rollers 2 cooperatingwith them are arranged one above the other. The product 3 to belaminated by compression is in this case inserted in an approximatelyhorizontal position between the pressure rollers 1, 2. However, it isalso possible to use a system in which the axes of rotation of thepressure rollers extend vertically or at another angle in such a mannerthat the product to be laminated by compression is inserted between thepressure rollers in a vertical position or in another angular position,if for any reason whatsoever this arrangement should prove advantageous.

In the case of the calendering device shown in FIGS. 1 and 2, the upperpressure rollers 1 are each mounted in pairs on an axis of rotation 4.The axis of rotation 4 is fixed in its center in a support strip 5 of apressure roller 1. The support strip 5 is vertically oriented and ismounted on a vertical piston rod 6. At the upper extremity of piston rod6 is mounted a pressure piston, which has the shape of a pressure plate7. The counterpressure rollers 2 are mounted in an analogous manner on ashort end of common spindle 9 which is fixed at its center in a supportstrip 10. The support strip 10 is fastened to a piston rod 11 which, atits lower extremity and in the manner of piston, carries a pressureplate 12.

The piston rods 6 and 11 are prevented from turning by, for example, ascrew 32 and a slot 33, and are mounted for sliding very freely in ballguide-sleeves 14, 15. The ball guide-sleeve 14 for the piston rods 6 ofthe pressure rollers are mounted in a common casing 16. In an analogousmanner, the ball guide-sleeves 15 for the piston rods 11 of thecounterpressure rollers are mounted in a common casing 17. The twocasings 16, 17 are fastened to common vertical pillars 18 which, inturn, are respectively provided with bases 19.

A pneumatic casing 22, closed by a closing plate 21, is connected tocasing 16 holding the ball guides 14 and is bolted to this casing 16.The piston rods 6 of all the pressure rollers 2 movably extend into thispneumatic casing 22. Between the pressure plates 7 mounted on thesepiston rods 6 and the closing plate 21, a closed hollow body 23 isarranged inside the casing 22 in the form of a flexible hose and isformed of very elastic rubber. Instead of being formed by a flexiblehose, the hollow body can also be formed by the closing plate 21 and arubber diaphragm that is tightly squeezed between the casing 22 and theclosing plate 21. The hollow body 23 is joined to a connecting pipe 24for the admission of compressed air. Under the effect of the compressedair, the hollow body 23 expands, applies itself against all the pressureplates 7 arranged side-by-side and exerts the same pressure on all thepressure plates 7.

The counterpressure rollers 2 are also actuated by pressure in a mannersimilar to that for pressure rollers 1. The pneumatic casing 27, closedby plate 26, is joined to casing 17 which defines the ball guide-sleeves15 for the piston rods 11 carrying the counterpressure rollers 2. Thepiston rods 11 provided with pressure plates 12 extend into thispneumatic casing 27. Between pressure plates 12 and plate 26, a closedhollow body 28 is arranged inside pneumatic casing 27 in the form of aflexible hose and is formed of very elastic rubber. The hollow body 28is joined to hose coupling 29. A pipe 30 connects the two feedercouplings 24 and 29 and thus the two hollow bodies 23 and 28 to eachother, so that an equalization of pressure is continually establishedbetween them. The pipe 30 is connected to an adjustable source ofcompressed air by means of conduit 31.

In the case of the calendering device illustrated in FIGS. 3 and 4, thepressure rollers 41 are mounted for rotation around the axles 42 whichin turn are each mounted in a pivoting piece 43. This pivoting piece 43is, in turn, mounted for rotation around a pin 44. The pin 44 is mountedin a support yoke 45. The support yoke 45 is mounted at the lowerextremity of piston rod 46. A piston 47 is mounted on the upperextremity of piston rod 46 and moves up and down inside pneumatic casing48 which has the form of a pressure cylinder. The pneumatic casing 48 isformed of two parts 48' and 48" which are bolted to each other by meansof a flanged joint 49. A rubber diaphragm 50 is squeezed between the twoflanged joints 49. The pneumatic pressure introduced by pressurecoupling 51 into the pneumatic casing 48 acts on the diaphragm 50 whichtransmits the pressure to piston 47.

As shown in FIG. 3a, in particular, it is also possible that in place ofa taut diaphragm which expands under pressure action, a diaphragm 50 isused of very flexible rubbery material of a shape and dimension thatfits the piston such that no stretching of the diaphragm is required,since this diaphragm 50 is in effect folded about itself. When thepiston is moving, it unfolds between the piston and the inside wall ofthe pneumatic casing. In this case, the distance between the surface ofthe piston and the inside wall of the cylinder should be such that,during this unfolding operation, the surfaces of diaphragm 50 which movewhile facing each other do not touch each other. Thanks to thisunfolding operation of diaphragm 50, there is also avoided any frictionbetween the surfaces which move towards each other since the "folding"involves a rolling motion.

The pneumatic casing 48 is fastened to a console 53 which also forms thesupport for a ball guide-sleeve 54. The piston rod 46 glides inside thisball guide-sleeve 54 with a minimum loss due to friction. Means areprovided for preventing piston rod 46 from turning around its axis. Theindividual consoles 53 are arranged side-by-side on a horizontal supportcrosspiece 55 which, together with the vertical pillars 56 and the lowerhorizontal support crosspiece 57, form the frame of the machine which ismounted for pivoting in its entirety on horizontal axles 58.

The counterpressure rollers 61 are mounted in a comparable manner. Theiraxles of rotation 62 are arranged in a pivoting piece 63 which, in turn,is mounted for revolving around pin 64 in yoke 65. The yoke 65 isfastened to the upper extremity of piston rod 66, the lower extremity ofwhich carries the piston 67. Piston 67 moves in the vertical directioninside pneumatic casing 68 which again is in the form of a pressurecylinder and which is constituted of two parts 68' and 68" joined by ajoint 69. A very elastic and greatly expandable diaphragm 70 is squeezedbetween the two flanges of joint 69 and transmits the pneumatic pressureinto the pneumatic casing 68 through feed pipe 71. The diameter ofpiston 67 is again smaller than the inside diameter of pneumatic casing68 to such an extent that despite the insertion of diaphragm 70 betweenthe piston and the inside wall of pneumatic casing 68, a friction-freemovement of piston 67 inside the pneumatic casing 68 will be possible.That is, the structure and operation of piston 67 and diaphragm 70correspond to that of piston 47 and diaphragm 50. The pneumatic casing68 is mounted on a console 73 which at the same time forms the assemblysupport for the ball guide-sleeve 74 in which the piston rod 68 slidesin a friction-free manner and without being able to turn around itsaxis. The consoles 73 are mounted side-by-side on the horizontal supportcrosspiece 57 of the frame of the pivotable machine.

Due to their own weight, the equipment elements move in the verticaldirection, so that the pressure roller 41 and the counterpressure roller42 always occupy a position at the lower extremity so long as they arenot lifted up into a higher position by the product 3 to be laminated bycalendering. After the passage of a product 3 to be laminated, theytherefore descend to their lowermost position and are partially raisedby the rigid sheet of product 3 to be laminated. In this manner,supplementary curving forces act on the sheet of glass. To avoidsubmitting the sheet of glass to such stresses, a pneumatic spring 76 isarranged between the yoke 65 and the console 73, this spring beingdimensioned or set in such a manner that the weight of the movableelements is compensated. Advantageously, a pneumatic spring 76 with alinear working curve is used. Thanks to the presence of pneumatic spring76, the adjustment forces--in the case of a change of position of thepressure rollers--are extremely weak, so that the adaptation of the topposition of the pressure rollers to the shape of the glass sheet iseffected solely upon the intervention of the glass sheet that isintroduced between the rollers, and requires no additional adjustmentmeasure. After the passage of the glass sheet between the pairs ofrollers, the pressure rollers remain in the top position which theyoccupy by virtue of the action of the raised glass sheet.

Certain ones of the counterpressure rollers 61, for example, two ofthem, are rotatably driven to transport the product 3 between thepressure rollers. Such a revolving carrying mechanism is illustrated inFIG. 4. A support plate 78 is mounted on yoke 65 and carries a drivemotor 79. The toothed drive wheel 80 drives a drive chain 81 whichtransmits the movement of rotation to a toothed wheel 82 mountedcoaxially on counterpressure roller 61 and rigidly joined to it. Thusthe rotation of the drive motor 79 rotates the rollers 61 to advance aproduct 3.

The bearings 84 carrying the pivoting axes 58 of the frame of themachine are mounted on appropriate pedestals 85.

The pressure coupling 51 terminating in each pneumatic casing 48 isconnected directly to a pressure coupling 71 which terminates at onepneumatic casing 68 so that the same pneumatic pressure always acts onpressure rollers 41 and on counterpressure rollers 61 cooperatingtherewith. A separate pressure coupling 86 feeds each set of thepressure couplings 51 and 71 with compressed air. A pressure reducingvalve 87 is arranged in each pressure coupling 86, by means of which thepressure therein can be adjusted. Separate sets of pressure couplingpressure reducing valves are provided for each cooperating pair ofpressure rollers and counterpressure rollers arranged side-by-side. Inthis manner, the pressure obtaining in each set of two rollers acting inopposite directions to each other can be regulated independent of theneighboring sets of pressure rollers, so that different compressionpressures can be set along the width of the calendering device.

The calendering device illustrated in FIGS. 5 and 6 is constructedprecisely as that illustrted in FIGS. 3 and 4, insofar as thearrangement and mounting of pressure rollers 41 and counterpressurerollers 61 are concerned, as well as the configuration of pistons 47 and67, pneumatic casings 48 and 68, diaphragms 50 and 70, weightcompensation pneumatic springs 76 and the revolving drive using drivemotor 79. The supply of pressure to pneumatic casings 48 and 68 by thepressure couplings 86, 51 and 71 is also effected in the same manner,with the pneumatic pressure adjustable to the desired value in each setof two elements working in opposite directions, independent of theneighboring systems. This is done in each case by means of a pressurereducing valve 87.

Contrary to the embodiments described above, the pressure rollers 41 donot, however, act directly on the product 3, but rather, a continuouscylindrical body 90 is inserted between the pressure rollers 41 and theproduct 3. The cylindrical body 90 is made of an elastically deformablematerial, whose elastic deformation capacity is so great that it canappropriately adapt itself to the shape of the glass sheet. Thecylindrical body 90 is supported at its two extremities by suitablethrust bearings 91 in such a manner as to be unable to slide laterally.It is so mounted without being secured and is held in its position bysupport rollers 92 which are mounted to revolve on support arms 93behind the calendering device, which support arms in turn are mounted onthe yokes 45 carrying the pressure rollers 41. The support rollers 92are dimensioned and arranged in such a manner that the central axis ofthe cylindrical body 90 is set off by the distance A behind the platedetermined by the axes of rotation of the pressure rollers andcounterpressure rollers, respectively. A stable positioning ofcylindrical body 90 is thusly obtained.

The cylindrical body 90 serves to uniformize the pressure forces exertedby the pressure rollers 41 on the product 3 in such a manner that a moreuniform surface pressure is exerted on this product. This isparticularly important when the product-to-be-laminated 3 is constitutedby a sheet of glass or a film of plastic material on which a relativelysoft layer of plastic material is to be applied as an anti-splinteringcoating or, in the case of a substrate of plastic material, as acovering layer to improve the resistance against scratches and scores.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and desired to be secured by letters patent ofthe United States is:
 1. A calendering device comprising:a frame; aplurality of pressure rollers mounted side-by-side in first direction; aplurality of counterpressure rollers mounted side-by-side in said firstdirection, each of said counterpressure rollers being positioned forcooperation with one of said pressure .[.rollres.]. .Iadd.rollers.Iaddend.to form a plurality of pairs of cooperating pressure andcounterpressure rollers; piston rod means for separately supporting eachof said pressure rollers and counterpressure rollers; means for movingeach said piston rod means in a second direction so that said rollers ofeach said pair of rollers move toward one another to calender a producttherebetween, said means for moving comprising:(a) .Iadd.at least onepair of .Iaddend.first and second fixed fluid tight casings fixed tosaid frame, (b) an elastic diaphragm for each said fixed casing tightlydividing each said fixed casing into two portions, (c) means forsupplying pressurized fluid to one of said two portions of each saidfixed casing, (d) .[.a plurality of pistons.]. .Iadd.at least one piston.Iaddend.in the other of said two portions of each said fixed casing,.[.all of said pistons.]. .Iadd.said at least one piston .Iaddend.in.Iadd.each .Iaddend.said first fixed casing being fixed to said pistonrod means of said pressure rollers and engaging said diaphragm in saidfirst fixed casing such that movement of said diaphragm due to fluidpressure in said one of said two portions of said first fixed casingpresses .[.all of said pistons.]..Iadd.said at least one piston.Iaddend.in .Iadd.each .Iaddend.said first fixed casing to move acorresponding pressure roller in said second direction, wherein .[.allof said pistons.]. .Iadd.said at least one piston .Iaddend.in .Iadd.each.Iaddend.said second fixed casing .[.are.]. .Iadd.is .Iaddend.fixed tosaid piston rod means of said counterpressure rollers and .[.engage.]..Iadd.engages .Iaddend.said diaphragm in said second fixed casing suchthat movement of said diaphragm due to fluid pressure in said one ofsaid portions of said second fixed casing presses .[.all of saidpistons.]. .Iadd.said at least one piston .Iaddend.in .Iadd.each.Iaddend.said second fixed casing to move a correspondingcounterpressure roller in said second direction, wherein said.[.piston.]. .Iadd.pistons .Iaddend.are spaced from any walls of said.Iadd.at least one .Iaddend.fixed casing; .[.and.]. .Iadd.means forcompensating for movements of said rollers and piston rod means due tothe weight thereof, .Iaddend. means for equalizing the pressure betweensaid diaphragms.Iadd., and ball guide sleeve means for guiding movementof said at least one piston with low friction, wherein said pressurerollers are positioned above said counterpressure rollers, and whereinfor said pressure rollers the means for supplying pressurized fluidsupplies the pressurized fluid to only an upper one of said portions ofeach said casings. .Iaddend.
 2. The device of claim 1, wherein.Iadd.each of .Iaddend.said .[.diaphragm.]. .Iadd.diaphragms.Iaddend.comprises an elongated hose, said one of said two portions ofsaid fixed casing comprising the interior of said hose.